Objective:To investigate the effect of PM2.5 in the air of Chengdu on rats′spatial learning and memory ability by Morris water maze.Methods:Thirty-two male SD rats screened by Morris water maze were randomly divided into control group,PM2.5 lower dosage group,PM2.5 middle dosage group,and PM2.5 higher dosage group(n=8).The rats were exposed to PM2.5 ,which was collected by EM-2062 AParticulates Sampler from July 14~(th) to 30~(th) of 2017 in Chengdu,by intratracheal instillation,and the exposing dosage was depended on rats′mass,that is 0.96 mg·kg~(-1) in lower dosage group,3.84 mg·kg~(-1) in middle dosage group,and 15.36 mg·kg~(-1) in higher dosage group.Learning abilities of those rats were estimated with Morris water maze 3weeks later,and the IL~(-1)β level was tested by ELISA.Results:Compared to the control,the escape latency time of treated rats was longer,and the higher dosage group has the longest escape latency time(P0.05),while there was a reverse correlation between the effective regional time of rats and PM2.5 dosage.Conclusion:PM2.5 in the polluted air of Chengdu has the ability to impair rats′ability of learning and memorizing,and this impairment was associated to the concentration of PM2.5 .